General (Pharmacology incl Regeneratives)

Question 1

Mechanism of biphosphonates

Answer 1

Osteoclast-related antiresorptive effect

Additional anti-inflammatory and pain relieving effects

Question 2

What conditions is there clinical efficacy for bisphosphonate use?

Answer 2

Chronic back soreness Lower tarsal OA Navicular disease

Question 3

What conditions in the racehorse are bisphosphonates proposed to be useful for?

Answer 3

NB Bisphosphonates banned BHA <3.5years - horse can never race under rules if tx 1) Reduction in stress fracture risk 2) OA 3) POD 4) Sesamoiditis 5) Subchondral lucencies NB these are proposal, opinion v divided. Some suggest incr. fracture risk with their use Recent Havemeyer concensus stated that Bisphosphonates have no place in POD

Question 4

Problem with bisphosphonates and fracture healing

Answer 4

Inhibit osteocyte apoptosis (which induces the repair cascade) Inhibit osteoclastic resorption which is the initial phase of repair

Question 5

Predominant cartilage type in bone, tendon and hyaline cartilage

Answer 5

Bone - Collagen type I Tendon - Collagen type I Hyaline cartilage - Collagen type II Tendon repair associated with high collagen III

Question 6

What is the target sub tourniquet pressure (STP) for IVRLP in horses?

Answer 6

Systolic blood pressure + 100mmHg

Question 7

Advantages and disadvantages of wide rubber vs pneumatic touniquets for IVRLP

Answer 7

Wide Rubber: +easy to apply +cheap -hard to standardise and maintain sub tourniquet pressure (STP) ie cant apply exact pressure of change throughout the procedure -Application techniques are more variable thus potentially more variation in IVRLP efficacy Pneumatic: + easy to standardise and maintain STP - more expensive and less readily available in clinical settings

Question 8

Likely clinical effects of ∝2s on lameness evaluations

Answer 8

No significant difference in head movement and pelvic movement asymmetry between time 0 and 20 min, and time 0 and 60 min in both xylazine and control groups Some horses with FL lameness changed grade, but this was not significant between xylazine vs control. No such change observed for HL lameness (Rettig 2016 EVJ)

Question 9

Main growth factors in PRP

Answer 9

Stored mainly in alpha granules

PDGF

TGFbeta

IGF I and II

VEGF

FGF (fibroblast)

PDEDF

Osteonectin, osteocalcin, fibronectin and thrombospondin also

Question 10

Recommended platelet numbers in RPR

Answer 10

P-PRP (pure or leucoreduced) displays slightly higher platelet (1.3–4.0 fold) and leukocyte counts (0.5–2.0 fold) than whole blood,

L-PRP (leukocyte PRP) has increased platelet (5-fold) and leukocyte (3-fold or more) counts when compared to whole blood

Some texts state should be concentrated 3-5X that in plasma, or have a count of 10⁶

Question 11

3 activating substances of PRP

Answer 11

Calcium chloride (CC)

Calcium gluconate (CG)

Bovine thrombin (BT)

Thrombin is the most potent platelet activator and plasma available extracellular calcium is necessary to continue later in depolarisation, alkalinisation and degranulation

Can also be activated by direct contact with collagen of treated tissues

Question 12

Which substance was deemed best for PRP activation by Giraldo 2017 (VCOT)?

Answer 12

Calcium gluconate (CG)

Gelation time is prolonged, GF release is significant and very comparable with BT, and calcium deposition in PRP clots is not evident when compared to clots obtained with CC.

Therefore advantageous over bovine thrombin and calcium chloride